Field
At least one example embodiment relates to energy harvesting devices.
Description of the Related Art
Energy harvesting, also known as power harvesting or energy scavenging, captures wasted energy (for example, solar power, thermal energy, wind energy, and kinetic energy) in everyday life and converts the captured energy into electric energy. Kinetic energy, such as continuous vibrations and discrete impacts, may be converted to the electric energy by using piezoelectricity. Piezoelectricity is an eco-friendly technology where piezo-electric materials absorb kinetic energy and convert the kinetic energy into the electric energy. The piezo-electric energy harvesting may be performed on a small scale, may have a wide selectivity of frequency environment, and high efficiency compared to other technologies that involve vibrational energy harvesting (e.g., an electrodynamic technology).
Piezo-electric energy harvesting may involve placing transducers at locations where vibrations or impacts frequently occur. The transducers may include various piezo-electric materials such as ceramics, polymers, and/or semiconductor oxides in a cantilever type, in a patch type, and/or in a diaphragm type. The structure of these transducers may be suitable for the characteristics of a vibrational environment, for example, vibrational frequency or acceleration. For example, the transducers may be roughly classified as either a vibration type or an impact type. A vibration type transducer may amplify the displacement of the transducer using resonance to increase the amount of piezo-electric power generation. An impact type transducer may cause the displacement of the transducer using force exerted by a load in a direct or indirect manner.
However, conventional energy harvesting devices have poor durability and poor power generation efficiency.